1 DesignSpaceDocument Python API
An object to read, write and edit interpolation systems for typefaces. Define sources, axes, rules, variable fonts and instances.
Get an overview of the available classes in the Class Diagram below:

UML class diagram of designspaceLib. Click to enlarge.
DesignSpaceDocument
AxisDescriptor
DiscreteAxisDescriptor
AxisLabelDescriptor
LocationLabelDescriptor
RuleDescriptor
Evaluating rules
SourceDescriptor
VariableFontDescriptor
RangeAxisSubsetDescriptor
ValueAxisSubsetDescriptor
InstanceDescriptor
Subclassing descriptors
The DesignSpaceDocument can take subclassed Reader and Writer objects. This allows you to work with your own descriptors. You could subclass the descriptors. But as long as they have the basic attributes the descriptor does not need to be a subclass.
class MyDocReader(BaseDocReader):
axisDescriptorClass = MyAxisDescriptor
discreteAxisDescriptorClass = MyDiscreteAxisDescriptor
axisLabelDescriptorClass = MyAxisLabelDescriptor
locationLabelDescriptorClass = MyLocationLabelDescriptor
ruleDescriptorClass = MyRuleDescriptor
sourceDescriptorClass = MySourceDescriptor
variableFontsDescriptorClass = MyVariableFontDescriptor
valueAxisSubsetDescriptorClass = MyValueAxisSubsetDescriptor
rangeAxisSubsetDescriptorClass = MyRangeAxisSubsetDescriptor
instanceDescriptorClass = MyInstanceDescriptor
class MyDocWriter(BaseDocWriter):
axisDescriptorClass = MyAxisDescriptor
discreteAxisDescriptorClass = MyDiscreteAxisDescriptor
axisLabelDescriptorClass = MyAxisLabelDescriptor
locationLabelDescriptorClass = MyLocationLabelDescriptor
ruleDescriptorClass = MyRuleDescriptor
sourceDescriptorClass = MySourceDescriptor
variableFontsDescriptorClass = MyVariableFontDescriptor
valueAxisSubsetDescriptorClass = MyValueAxisSubsetDescriptor
rangeAxisSubsetDescriptorClass = MyRangeAxisSubsetDescriptor
instanceDescriptorClass = MyInstanceDescriptor
myDoc = DesignSpaceDocument(MyDocReader, MyDocWriter)
Helper modules
fontTools.designspaceLib.split
See Scripting > Working with DesignSpace version 5 for more information.